Children showing symptoms of obsessive-compulsive behaviour are more likely to develop the full-blown disorder when they grow up, says a New Zealand study.

Lead researcher, Barcelona University pyschologist Miguel Angel Fullana, based his findings on 1,000 children in the Dunedin longitudinal study, which started in 1973.

He called for a focus on preventive measures for children, "since we've seen that the risk is much lower amongst the rest of the population".

His team observed the children for the repeated presence of obsessive ideas such as recurrent and undesired thoughts to harm others, compulsive rituals such as handwashing and repeatedly carrying out meaningless activities.

"Researchers for the first time have obtained objective proof that there is a correlation between obsessions and compulsions in childhood and the probability of suffering from an obsessive-compulsive disorder (OCD) as an adult," Dr Fullana said.

The eight percent of girls and boys in the study - who showed symptoms of obsessive or compulsive behaviour at age 11 â were six times more likely than others to suffer from an OCD in adulthood.

But Dr Fullana noted that such behaviours were very common among children aged eight to 10, while the percentage of adults with OCD was less than two percent.

The New Zealand study could be applied around the world, Dr Fullana said.

OCD is generally accompanied by a family history. Current treatments have a strong psychological component based on screening prevention strategies, as well as drug therapy based on anti-depressants.

Compulsions are usually linked to obsessional thoughts, such as worry about dirty hands can lead to excessive handwashing to relieve the anxiety caused by the thoughts.

Common obsessions include:

* Dirt and contamination which leads to excessive washing and avoiding possible dirt.

* Doubt, leading to checking that things have been done properly â like locks being locked and stoves turned off.

* Unusual or repulsive images. These may be about religion, sex, violence or suicide and may raise unrealistic fears about the safety of the person or their family or whanau.